<i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-Tetraalkyl-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxamides: Novel Chiral Auxiliaries for Asymmetric Simmons–Smith Cyclopropanation of Allylic Alcohols and for Asymmetric Diethylzinc Addition to Aldehydes

Abstract

Abstract The newly introduced title compounds were found to be efficient chiral auxiliaries for the asymmetric Simmons–Smith cyclopropanation of allylic alcohols and for asymmetric addition of diethylzinc to aldehydes. For example, Simmons-Smith cyclopropanation of cinnamyl alcohol in the presence of N,N,N′,N′-tetraethyl-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxamide (1b) proceeded with high enantioselectivity of 94% ee and addition of diethylzinc to benzaldehyde in the presence of N,N,N′,N′-tetraisopropyl-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxamide (1e) proceeded with enantioselectivity of 99% ee. Although the reaction mechanism of these reactions is still nuclear, a monomeric seven-membered 2,2′-dihydroxy-1,1′ -binaphthyl-3,3′-dicarboxamide (1)–Zn complex is considered to be an active species which catalyzes the above reactions, on the basis of NMR experiments.